The present invention relates to a laser processing apparatus and method for using laser beams in laser machining processes such as processes for opening holes in a work being processed such as an electronic circuit board.
One example of a laser processing apparatus of this type that is known is configured so that, as diagrammed in FIG. 4, minute holes are perforated in work being processed such as a board 7 by laser beam irradiation. With this laser processing apparatus, a laser beam 2 is output from a laser oscillator 1, reflected by a reflecting mirror 3a to change its direction, and then branched into two directions by a beam splitting device 9. The branched laser beams 2a and 2b are guided, respectively, by reflecting mirrors 3b and 3c and by reflecting mirrors 3d to 3f toward galvanometers 4 and 5 equipped with galvano-mirrors with axes in the P and Q dimensions, after which the laser beams 2a and 2b have their directions of irradiation changed by the sweep of the galvanometers 4 and 5, are input to fxcex8 lenses 6a and 6b, respectively, and focused. Then the laser beams 2a and 2b are irradiated and scanned in the X and Y directions in a processing area B within predetermined ranges on the board 7 that is positioned by an XY table 8. The XY table is then moved, and the next processing areas are laser-processed.
In laser processing methods that use the laser processing apparatus described above, however, when processing is performed to open holes in the board 7 by the laser beams 2c focussed by the fxcex8 lenses 6a and 6b, due to the necessity of realizing roundness in the holes, the processing areas B are limited to approximately 50 mm or so in the X and Y dimensions, respectively, by the effective diameters of the fxcex8 lenses 6a and 6b. The dimensions of the board 7 are such that the sides measure 200 to 500 mm or so, which is roughly the same over the entire processing area A. Accordingly, if the dimensions of the board 7 are 500 mm in the X dimension and 350 mm in the Y dimension, for example, a matrix of 70 processing areas B is necessary in order to process the entire processing area A.
The dimensions of the board 7 are various, however, and, if the interval between the two fxcex8 lenses 6a and 6b is constant, there will be cases where even though processing with one fxcex8 lens is finished the processing with the other fxcex8 lens will not be finished. In such cases it is necessary to continue processing with the other fxcex8 lens for a considerable time, to the detriment of processing efficiency. It is also necessary to implement measures so that the one fxcex8 lens laser beam is not being irradiated onto the board 7 while processing is in progress with the other fxcex8 lens, and energy is lost during that time due to the wasted laser irradiation.
Thereupon, an object of the present invention is to provide a laser processing apparatus and method that resolves such problems as those described in the foregoing, wherewith changes in the dimensions of the work being processed can be coped with, and laser processing can be performed efficiently and with high productivity.
In order to achieve the object stated above, the present invention provides a laser processing apparatus comprising: a laser oscillator for outputting laser beams; a beam splitting device for branching the laser beam output from the laser oscillator into a plurality of laser beams; a plurality of scanning devices for guiding the branched laser beams to processing positions on a work being processed; a plurality of focusing devices for focusing and irradiating the branched laser beams onto said work being processed, thereby performing laser processing with the branched laser beams in a processing area within predetermined ranges on said work being processed; an XY table for carrying thereon the work being processed and for moving said work relative to said plurality of focusing devices; and an adjustment member for automatically adjusting interval between center points of said plurality of focusing devices in correspondence with size of entire processing area on said work being processed.
As based on the present invention, when the board or other work being processed is moved relative to the focusing devices and the processing areas are sequentially processed, the points in time when the laser processing in all of the focusing devices is finished are made to coincide by automatically adjusting the interval between the center points of the focusing devices in correspondence with the size of the entire processing area of the work being processed. Hence it is possible to eliminate the wasted work time and wasted laser irradiation resulting from the non-coincidence of laser process finishing times that has been a problem in the prior art, and to perform laser processing efficiently and with high productivity.
In the invention described in the foregoing, it is preferable if a light path length adjustment member is also provided for adjusting the light path lengths so that the light path lengths from the point where the light beam is branched by the beam splitting device to the processing points where the light beams are focused by the focusing devices after passing through the scanning devices are made the same length. By providing light path length adjustment member, the non-coincidence in light path length arising in conjunction with adjusting the interval between the center points of the focusing devices can be corrected, and the focused state of the laser beams can be maintained the same, wherefore simultaneous processing can be performed precisely on the work being processed.
In order to achieve the object stated above, the present invention provides a laser processing method wherein: a laser processing apparatus is employed wherein: a laser beam output from a laser oscillator is branched into two beams by branching means; the branched laser beams are respectively guided by scanning means to process positions on work being processed and focused and irradiated by focusing means onto the work being processed, thereby performing laser processing with the two laser beams on processing areas within predetermined ranges on the work being processed; the work being processed is moved relative to the two focusing means; and the next processing areas are sequentially laser-processed by the laser beams irradiated from the focusing means; and laser processing is performed, automatically adjusting the interval between the center points of the focusing means in correspondence with the size of the entire processing area on the work being processed so that that interval is always xc2xd the length of the entire processing area.
As based on the present invention, using two laser beams, the interval between the center points of the two focusing devices can be automatically adjusted, and laser processing can be performed efficiently and with high productivity.
While novel features of the invention are set forth in the preceding, the invention, both as to organization and content, can be further understood and appreciated, along with other objects and features thereof, from the following detailed description and examples when taken in conjunction with the attached drawings.